The defender made 35 appearances for the Emirates Stadium outfit last season but a calf injury all but ended his season in February.
Gallas is currently part of a French squad in disarray at the World Cup where his side picked up just one point and scored just once as they crashed out of the tournament at the group stage on Tuesday.
And Wenger believes that the uncertainty over Gallas’ future may have contributed to his poor form in South Africa.
“I don’t know if Gallas has been perturbed by his departure from Arsenal,” said Wenger.
“I knew he wouldn’t be at 100 percent for this tournament. The question for the manager is to know if he should have called up Gallas while knowing he’s not 100 percent.
“He’s played 35 minutes in four months before [the World Cup] and it’s not enough to get into a competition like this.”
Gallas and his French team-mates refused to train on Sunday after Nicolas Anelka was sent home from the World Cup.
And the 1998 winners' hopes of squeezing through to the second round ended after losing 2-1 to hosts South Africa.
The 32-year-old made 101 appearances during his time at Arsenal and scored 17 goals. It has been suggested that his wage demands proved to be the stumbling point in contract negotiations.
According to reports, Inter Milan and Real Madrid are both interested in signing Gallas.
The veteran’s representatives have also been weighing up lucrative offers from the United States and the Middle East but Gallas is adamant he can still perform at the highest level in Europe.
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